Some Entities (Materials and Jobs) can each be grouped together into "Sets" to organize them better. Sets therefore play a similar same role as folders in an operating system environment, for example.

There are two types of sets, unordered and ordered. As the names imply, an unordered set contains entities without any order and may contain nested sets. The sets are created unordered by default. On the other hand an ordered set includes one-level set of entities with a specific order.